I've tried to write a few stories.

They failed miserably.

BUT ANYWAY, I wouldn't go looking for fame immediately. I wouldn't expect it, either. It might come, but I'm sure Kate DiCamillo or J.K. Rowling or Rick Riordan or Chris D'Lacey (or whoever the heck Rebecca Stead is) could all tell you that when they first started, they weren't thinking of money or fame.

Hope this helped, but as you said, there's really no right or wrong way to write.

"If you have the lowest of expectations, you'll never be disappointed." -Halt, The Ranger's Apprentice 

First off, Livv, I'll tell you that unless you're writing to get people hurt or writing outright propaganda or something, there is almost no bad reason to want to write, and yours is one of the best. A lot of people want to write to make a difference in someone's life, but that's also one of the motivations that is most easily disappointed, because it has little obvious gratification. Obviously, when you get to say, J.K. Rowling or John Green level, you get so many fan letters flooding in talking about how your book changed their life that after a while you can't even read them all. But in our late pre-teen and early teen ages, that's obviously not a realistic goal, so how do we feel like we're reaching something? 

We appreciate the little things. You can post your stories here, where there are lots of people willing to provide feedback and read it and appreciate it. You've already had stories published - I haven't had anything published in my entire life. But I share my stories with my friends, and today my lit teacher asked me to read a poem I wrote at the annual breakfast that they host in honor of the eighth graders. I thought it was terrible. But as I read it, I felt the eyes of the room upon me and a lot of parents really liked it, and one of the most cynical people in the grade said it was 'pretty good', so I'd obviously done something right. 

The point is, people won't always become a new person and change dramatically after they read your stories. But the ghost of a smile, the hint of a memory, a glimmer in one's eyes may be all it takes. You may not even know if someone who reads Rolling Stone remembers your story to this day, but they may well recall it fondly.

Above all, remember that there are infinite motivations to write fiction, each more noble and far-reaching than the other, but one matters above all the others: enjoying it. If you like what you're doing, even if you're not fully happy with the result or with audience reactions, eventually you'll feel like it was worth it all along, whether if the only people who've heard it are your dog and a Venus Flytrap, whether it gets published in a magazine, whether you write every day or once a week, whether you're J.K. Rowling or Rebecca Stead. 

That was longer than I intended it to be, and also probably more idealistic.

As an addendum, NaNoWriMo and its sister websites are great for writing motivation. 

First off, high five! I've also published in Stone Soup Magazine! 

There's nothing wrong with wanting to be a writer! It's, I think, one of the purest ambitions in the world. So long as your intention is NOT to corrupt the youth of the next generation, which yours obviously ISN'T, there's no reason why you shouldn't become a writer if you want to! Of course, there's no guarentee that you will be famous, but as long as you love doing it, why not? That's my philosophy, anyway. And you're young! You have your whole life to get through pitfalls and things.

Speaking of Kate DiCamillo, she waited until she was 30 to start really writing, even though she had ambitions in college. So even if it might take ten years, you'll still be only in your twenties. That's the great thing about writers. They can keep writing until old age.

Hope that helps a little bit!